Mahito deftly uses Yoshino's admiration toward him to make him fight Itadori. Yoshino races toward vengeance and Itadori exchanges blows with him to try and make him explain his motive, which leads to him learning the cruel truth from Yoshino's lips. That's when Mahito creeps up beside them and--
I don't know what your motive is. 
I'm sure you have a reason for doing this.
.لا أعرف دوافعك. لكن لا بدّ من وجود سبب ما
Ich kenn deine Motive nicht.
Aunque no sé por qué lo haces,
Aunque no sé por qué lo haces,
Je sais pas ce qui t’arrive.
Non ho idea di quali siano le tue motivazioni.
Eu não sei o que te motiva.
Не знаю, что тобой движет.